A rare discovery believed to date back to the musket wars of the early 19th century has created huge interest at the site of road widening in Tauranga.
Contractors were widening the side of State Highway 29 near the Maungatapu Bridge when project archaeologist Sian Keith noticed an unusual pattern in the exposed ground.
Numerous kumara and fire pits had already been found when she saw what appeared to be a long line of pits.
''Looking at it more carefully, I saw they were all connected.''
It then dawned on her that she was looking at a defensive trench, dug to protect the nearby pa, Puwharariki.
A test dig confirmed that it was indeed a trench system, measuring about 40m long and with zig-zag buttresses to stop one inside shot sweeping the whole length of the ditch.
While she was not surprised at finding kumara pits, given the history of Maori habitation in the area, the trench was completely different.
Earthworks came to an immediate halt and a team of six archaeologists were recruited to remove the fill from the ditch and reveal how it would have looked at least 180 years ago.
Miss Keith said she had never found a defensive trench in her 20 years working as an archaeologist.
''It is quite rare to find them. It has not been disturbed from the day it was backfilled . . . it is a really good example of a rifle trench.''
Five musket balls and a gun flint have so far been sifted out of soil dug from the trench, leading to speculation that it dated back to the New Zealand Land Wars or the earlier inter-tribal Musket Wars.
Miss Keith said the site was away from other well-known battle sites around Tauranga and, depending on the date, could add important information to the historic record.
The direction of the trench indicated it was built to defend the pa from an attack by warriors arriving in a waka, perhaps along a weak point in the defensive system.
A representative from local hapu Ngai Tukairangi, Ngati He and Ngati Tapu was monitoring the excavation.
The road was being widened to provide room for the construction of a central median barrier, with the excavation and recording expected to take about two weeks before the area was covered over to become the shoulder of the road.
The Bay's state highways manager Niclas Johansson of the New Zealand Transport Agency said the find could be nationally significant so it was important to take the time to find out as much as they could to honour tangata whenua.
Ngai Te Rangi iwi kaumatua Puhirake Ihaka said the archaeologists were finding the remains of Puwharariki Pa, which sat between Te Ngaio Pa by the bridge, and Oruamatua Pa, which sat on the big headland off SH29 towards Baypark.
He suspected that the trench was built to protect the pa from raiding parties during the Musket Wars from 1818 to the 1830s. The use of muskets by warring Maori signified the demise of hand-to-hand fighting using taiaha and mere.
Mr Ihaka said the trench was a very significant find and would be registered as wahi tapu to mark its importance for future generations.
Kihi Ngatai (Ngai Te Rangi) said the last time he had seen a trench system like this was at the historic battleground of Gate Pa before roading and development destroyed Maori defensive earthworks surrounding the battle pa.
''It makes you wonder how old its is.''
SH29 roading project
- Trench discovery delays project by about two weeks
- Central median barrier completed by the middle of the year
- Speed limit 70km/h through construction site